package 实验3;

import java.util.Scanner;

/**
 * @author : niu niu
 * @version : 1.0.0
 * @date : 2022/11/29 14:07
 */
public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int n = s.nextInt();
        System.out.println(climbStairs(n));
    }
    public static long climbStairs(int n) {

        return (long) Math.pow(2,n-1);
    }
}
